Sophisticated computer systems and electronic devices are providing rapid growth in portable electronic devices. These devices typically require medium for the storing of information, such as a phase change polymer or magnetic material. Typically, these devices include some form of read and write mechanism for transferring data to and from the device.
Storage devices are conventionally larger in capacity and somewhat slower in response time than main memory devices. For example a hard drive may provide several gigabytes of storage with access times of about 6 milliseconds, whereas main memory RAM may provide a few hundred kilobytes with access times orders of magnitude faster than a hard drive.
With fast access main memory devices such as RAM, increasing the storage capacity generally also increases the complexity of the physical memory structure as well as the complexity of the control logic and interface mechanism. By utilizing a moving read/write device as opposed to hard wiring each and every data location, storage devices can provide large capacity while minimizing the required overhead support.
To write information, the storage device positions its write device relative to the location on the medium where the information is to be stored. The storage of information is commonly referred to as writing data. To read the information back, the device must position its read device relative to the location on the medium where the information was previously written. For both operations, proper tracking and alignment are required to insure that the proper data is transferred.
Traditionally, a single read/write device operates to read/write an entire stream of user data in series. For example the data “28088” is written in series to one data track. The user data is conventionally represented in appropriate machine readable code—most commonly symbolized as block patters of “1” and “0”. The speed of the device is in part limited by the speed of the read write device and how fast it can, 1) move over the media or data track, and 2) transfer information to or from the medium or data track.
Storage devices such as memory cards are often intended for use in portable electronic devices such as cameras and MP3 players. As such, it is desirable for such storage devices to be as physically small as possible. Such a desire imposes manufacturing constraints as to the size of individual components. Portable devices are also often subjected to motion shock. To avoid damage to data, it is desirable for the memory device to be fabricated so as to tolerate the stress of motion shock.
Portable storage media devices often use one or more micromovers, i.e. tiny movement devices that impart relative movement between the read/write device and the data storage medium. The loss or damage of a read/write device or misalignment of the medium by the micromovers may result in corrupted data. Such loss or damage may occur as the result of motion, shock and or other factors. In an effort to increase the speed of data access, the micromovers may be operated at a high speed. High speed often compounds problems should a read/write device fail and contact the data storage media in an abnormal fashion.
Because data is written to a single location, such as a data track, by a single device, the entire stream of user data may be lost if the read/write device malfunctions. It is not uncommon for memory modules to occasionally suffer damage to the read/write device or the data tracks established in the media when subjected to motion shock and other environmental factors. In storage devices fabricated on a small scale for appropriate use in portable devices, the likelihood for manufacturing errors to occur and disable a read/write head or data media is certainly increased.
One frequently employed strategy to help reduce data corruption is the provision of a considerable amount of buffering data space between allocated data tracks. However, each allocation of buffering space reduces the space available for actual data storage. With a desire to provide maximum storage space, each allocation of buffer space is somewhat counter productive.
Hence, there is a need for an ultra-high density storage device that overcomes one or more of the drawbacks identified above.